A novel dimmable electronic ballast for street lighting with HPS lamps

A new high frequency dimmable ballast for high-pressure sodium lamps has been developed. This paper describes the novel ELGADI (electronic ballast for gas discharge) topology, which comprises a dedicated interface for dimming and lamp diagnostics. Lamp power can be controlled using a power line modem or an intelligent timer module. A new improved starting technique is also evaluated by monitoring electrode material sputtering. Lamp efficiency is measured over the service life of a lamp with the ELGADI ballast at full power (100%) and in dimming mode (50%). These tests show that dimming has a beneficial effect on costs over the service life of a lamp. The ELGADI ballast has a better lumen efficiency maintenance during lamp service life. The differences between this lamp power control method and ferromagnetic ballasts are explained.